Genealogy is the study of a family's lineage. It often encompasses 5 dimensions:
Biological (Who)—Online and offline research into one's family tree. This may include collateral lines and through the use of DNA can include deep ancestral origins.
Temporal (When)—Researching and recording when our ancestors were born, baptized, married, had children, died, and were buried. This may also include capturing other major and minor life events that can be embodied in a timeline.
Socio-economical (What)—Researching, recording, and understanding the social and economic context in which our ancestors lived their lives. This may include religious and political party affiliations, religious and cultural practices, church membership, political offices held, military service and rank, group memberships, education, occupations held, supplier and customer relationships, income, investments, net worth, asset analysis, interests, attitudes, and opinions.
Historical (Why)—Researching and understanding the historical context within which our ancestors lived—social and religious movements, macro-economics, cultural, political, and technological trends, regional rivalries, war, et. al.
Geographical (Where)—Researching and recording the location of ancestral life events.
Much of a researcher's initial focus is on capturing the first two dimensions—Who and When. Where is almost incidental—a traceable source citation for future research. As researchers gain more experience and can devote the time—some will focus on the dimensions of What and Why to gain insight into their ancestors lives in context and maybe getting a deeper understanding of themselves in the process.
However, when you take into account available technology and the relative lack of mobility before the introduction of the steam train and the automobile, or where physical geography hindered mobility, or where geography and culture intersect—the Where dimension becomes the dominant dimension in your family tree. The Where determines the pool of potential mates. The Where determines access to food, water, energy, and raw materials. The Where influences one's economic opportunity but also one's risk profile with respect to war, crime, natural and man-made disasters, pestilence, disease, and famine.
Moreover location is an actual determinant in the probability that two people within geographic proximity are related. Tobler's (1970) first law of geography—that everything is related to everything else but near things are more related than distant things—has been rigorously verified in the field of geographical genetics. It has also been demonstrated in the field of geographical genetics that relatives will exhibit some degree of spatial proximity and spatial neighbors will exhibit some average excess of relatedness.